Trial Outcomes & Findings for Study to Evaluate NBI-921352 as Adjunctive Therapy in Subjects With SCN8A Developmental and Epileptic Encephalopathy Syndrome (SCN8A-DEE) (NCT NCT04873869)

NCT ID: NCT04873869

Last Updated: 2025-10-16

Results Overview

Recruitment status

TERMINATED

Study phase

PHASE2

Target enrollment

8 participants

Primary outcome timeframe

Planned time frame: Baseline to Week 16

Results posted on

2025-10-16

Participant Flow

Study was prematurely terminated due to sponsor decision. Due to the early termination, only 8 participants were enrolled and completed the study. As prespecified, analyses were pooled by treatment received (NBI-921352 or placebo), rather than specific dose level received.

Participant milestones

Participant milestones
Measure	NBI-921352 Participants received oral doses of NBI-921352 3 times a day based on body weight.	Placebo Participants received oral doses of placebo matching NBI-921352 3 times a day.
Overall Study STARTED	4	4
Overall Study Received Study Drug	4	4
Overall Study COMPLETED	4	4
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Study to Evaluate NBI-921352 as Adjunctive Therapy in Subjects With SCN8A Developmental and Epileptic Encephalopathy Syndrome (SCN8A-DEE)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	NBI-921352 n=4 Participants Participants received oral doses of NBI-921352 3 times a day based on body weight.	Placebo n=4 Participants Participants received oral doses of placebo matching NBI-921352 3 times a day.	Total n=8 Participants Total of all reporting groups
Age, Continuous	4.46 years STANDARD_DEVIATION 2.60 • n=5 Participants	9.17 years STANDARD_DEVIATION 4.87 • n=7 Participants	6.81 years STANDARD_DEVIATION 4.40 • n=5 Participants
Sex: Female, Male Female	2 Participants n=5 Participants	2 Participants n=7 Participants	4 Participants n=5 Participants
Sex: Female, Male Male	2 Participants n=5 Participants	2 Participants n=7 Participants	4 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	3 Participants n=5 Participants	4 Participants n=7 Participants	7 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) White	4 Participants n=5 Participants	4 Participants n=7 Participants	8 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants

PRIMARY outcome

Timeframe: Planned time frame: Baseline to Week 16

Population: Due to early study termination, analyses of efficacy data were not performed due to an insufficient sample size to allow for meaningful statistical analysis of the data, as pre-specified in the protocol.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline to Week 16

Treatment response was defined as a ≥50% decrease from baseline in 28-day seizure frequency for countable motor seizures during the treatment period of the study.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline, Week 6 to Week 16

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline to Week 16

Treatment response was defined as a ≥25%, ≥50%, ≥75%, or 100% decrease from baseline in 28-day seizure frequency for countable motor seizures during the treatment period of the study.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline, Week 6 to Week 16

Treatment response was defined as a ≥25%, ≥50%, ≥75%, or 100% decrease from baseline in 28-day seizure frequency for countable motor seizures during the treatment period of the study.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Up to Week 16

The CGIC scale, which is based on a 7-point scale (range: 1=very much improved to 7=very much worse), was used to rate the overall global improvement since the initiation of study treatment dosing, as rated by the investigator (or qualified designee).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Up to Week 16

The GIC scale was used to assess the parent/caregiver's impression of change in the participant's overall condition since starting study treatment and was rated on a 7-point scale (1=very much improved to 7=very much worse).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline to Week 16

The CGIS scale was used to assess overall severity on a 5-point scale (range: 1=normal, not at all ill to 5=among the most extremely ill).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Planned time frame: Baseline through Week 16

The GIS scale was used to assess overall severity on a 5-point scale (range: 1=none to 5=very severe).

Outcome measures

Outcome data not reported

Adverse Events

NBI-921352

Serious events: 2 serious events

Other events: 4 other events

Deaths: 0 deaths

Placebo

Serious events: 1 serious events

Other events: 4 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	NBI-921352 n=4 participants at risk Participants received oral doses of NBI-921352 3 times a day based on body weight.	Placebo n=4 participants at risk Participants received oral doses of placebo matching NBI-921352 3 times a day.
Infections and infestations Parainfluenzae virus infection	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Urinary tract infection	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Seizure	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Respiratory, thoracic and mediastinal disorders Acute respiratory failure	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.

Other adverse events

Additional Information

Neurocrine Medical Information

Neurocrine Biosciences

Phone: +1 877-641-3461

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	NBI-921352 n=4 participants at risk Participants received oral doses of NBI-921352 3 times a day based on body weight.	Placebo n=4 participants at risk Participants received oral doses of placebo matching NBI-921352 3 times a day.
Cardiac disorders Tachycardia	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Gastrointestinal disorders Constipation	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Gastrointestinal disorders Vomiting	50.0% 2/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
General disorders Gait disturbance	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	50.0% 2/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
General disorders Pyrexia	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations COVID-19	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Enterovirus infection	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Nasopharyngitis	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	50.0% 2/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Otitis media	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Pneumonia	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Rhinovirus Infection	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Sinusitis	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Upper respiratory tract infection	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Infections and infestations Urinary tract infection	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	50.0% 2/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Injury, poisoning and procedural complications Arthropod sting	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Injury, poisoning and procedural complications Face injury	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Injury, poisoning and procedural complications Fall	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Injury, poisoning and procedural complications Spinal compression fracture	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Investigations Eosinophil count increased	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Investigations Urine leukocyte esterase positive	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Investigations White blood cells urine	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Musculoskeletal and connective tissue disorders Arthralgia	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Musculoskeletal and connective tissue disorders Back pain	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Musculoskeletal and connective tissue disorders Myalgia	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Musculoskeletal and connective tissue disorders Neck pain	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Coordination abnormal	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Drooling	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Lethargy	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Seizure	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Nervous system disorders Somnolence	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Renal and urinary disorders Urinary retention	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.
Skin and subcutaneous tissue disorders Rash papular	25.0% 1/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.	0.00% 0/4 • Up to 30 weeks Safety Analysis Set: Included all participants who received at least 1 dose of study treatment.